tests/test-fenv-except-state-3.c

   1 /* Test of saving the floating-point exception status flags.
   2    Copyright (C) 2023-2025 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Bruno Haible <bruno@clisp.org>, 2023.  */
  18
  19 #include <config.h>
  20
  21 /* Specification.  */
  22 #include <fenv.h>
  23
  24 #include <stdio.h>
  25
  26 #include "fpe-trapping.h"
  27 #include "macros.h"
  28
  29 /* musl libc does not support floating-point exception trapping, even where
  30    the hardware supports it.  See
  31    <https://wiki.musl-libc.org/functional-differences-from-glibc.html>  */
  32 #if HAVE_FPE_TRAPPING && (!MUSL_LIBC || GNULIB_FEENABLEEXCEPT)
  33
  34 /* Check that fesetexceptflag() does not trigger a trap.  */
  35
  36 static volatile double a, b;
  37 static volatile long double al, bl;
  38
  39 int
  40 main ()
  41 {
  42   fexcept_t saved_flags_1;
  43
  44   /* Test setting all exception flags.  */
  45   if (feraiseexcept (FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW | FE_INEXACT) != 0)
  46     {
  47       fputs ("Skipping test: floating-point exceptions are not supported on this machine.\n", stderr);
  48       return 77;
  49     }
  50
  51   /* Fill saved_flags_1.  */
  52   ASSERT (fegetexceptflag (&saved_flags_1,
  53                            FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW | FE_INEXACT)
  54           == 0);
  55
  56   /* Clear exceptions from past operations.  */
  57   feclearexcept (FE_ALL_EXCEPT);
  58
  59   /* An FE_INVALID exception shall trigger a SIGFPE signal, which by default
  60      terminates the program.  */
  61   if (sigfpe_on_invalid () < 0)
  62     {
  63       if (test_exit_status != EXIT_SUCCESS)
  64         return test_exit_status;
  65       fputs ("Skipping test: trapping floating-point exceptions are not supported on this machine.\n", stderr);
  66       return 77;
  67     }
  68
  69   /* Attempt to set the FE_INVALID exception flag.  */
  70   _GL_UNUSED int rc = fesetexceptflag (&saved_flags_1, FE_INVALID);
  71   /* On older i386 and on PowerPC, there is no way to implement
  72      fesetexceptflag() such that it does not trigger a trap.  fesetexceptflag()
  73      is expected to fail in this case.  */
  74 # if !((defined __i386 || defined _M_IX86) || defined __powerpc__)
  75   ASSERT (rc == 0);
  76 # endif
  77
  78   /* Do a harmless floating-point operation (since on some CPUs, floating-point
  79      exceptions trigger a trap only at the next floating-point operation).  */
  80   a = 1.0; b = a + a;
  81   al = 1.0L; bl = al + al;
  82
  83   return test_exit_status;
  84 }
  85
  86 #else
  87
  88 int
  89 main ()
  90 {
  91   fputs ("Skipping test: feenableexcept not available\n", stderr);
  92   return 77;
  93 }
  94
  95 #endif